The invention disclosed herein relates generally to the field of perimeter security and barrier and/or anti-ram (referred to below simply as “anti-ram”) devices and systems which, e.g., protect against vehicle penetration or channel vehicle traffic, etc. In particular, embodiments of the invention relate to vehicle anti-ram systems that can be mounted on existing or partially or entirely prepared surfaces. Embodiments of the invention can be mounted on existing surfaces such as streets, sidewalks and soil without any or with minimal site preparation, although the same or similar embodiments or variations may also be installed in sites which involve site preparation or construction associated with installation and/or operation of one or more embodiments. According to some embodiments, such anti-ram systems comprise one or more bollards.